From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andi Kleen <ak@linux.intel.com>
Subject: Re: qemu polling KVM_IRQ_LINE_STATUS when stopped
Date: Thu, 19 Oct 2017 17:34:49 -0700
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To: Paolo Bonzini <pbonzini@redhat.com>
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On Wed, Oct 18, 2017 at 09:24:33PM +0200, Paolo Bonzini wrote:
> On 18/10/2017 19:49, Andi Kleen wrote:
> > 
> > The ioctl appears to be the PIC timer
> > 
> >   - 6.36% __GI___ioctl                                                                                                                                ▒
> >            kvm_vm_ioctl                                                                                                                                   ▒
> >            kvm_set_irq                                                                                                                                    ▒
> >            kvm_pic_set_irq   
> 
> PIC is the interrupt controller, why do you say the timer?  What is the
> QEMU side of the call stack?


I did some more sampling in gdb this time.

All the timer call backs I caught are rtc_period_timer.

Perhaps that needs to be stopped when the guest is stopped?

It also calls the ioctl:

#0  0x00007f73d97175e0 in ioctl () from target:/lib64/libc.so.6
#1  0x000055ed03c7ec82 in kvm_vm_ioctl (s=s@entry=0x55ed06ba2000, type=<optimized out>) at /usr/src/debug/qemu-2.9.1/kvm-all.c:2136
#2  0x000055ed03c7fb15 in kvm_set_irq (s=0x55ed06ba2000, irq=<optimized out>, level=<optimized out>) at /usr/src/debug/qemu-2.9.1/kvm-all.c:1001
#3  0x000055ed03cef2c0 in kvm_pic_set_irq (opaque=<optimized out>, irq=<optimized out>, level=<optimized out>)
    at /usr/src/debug/qemu-2.9.1/hw/i386/kvm/i8259.c:114
#4  0x000055ed03cba196 in qemu_irq_raise (irq=<optimized out>) at /usr/src/debug/qemu-2.9.1/include/hw/irq.h:16
#5  rtc_periodic_timer (opaque=0x55ed06f88580) at /usr/src/debug/qemu-2.9.1/hw/timer/mc146818rtc.c:198
#6  0x000055ed03faf1f0 in timerlist_run_timers (timer_list=0x55ed06aafa40) at /usr/src/debug/qemu-2.9.1/util/qemu-timer.c:536
#7  0x000055ed03faf3f7 in qemu_clock_run_timers (type=QEMU_CLOCK_HOST) at /usr/src/debug/qemu-2.9.1/util/qemu-timer.c:547
#8  qemu_clock_run_all_timers () at /usr/src/debug/qemu-2.9.1/util/qemu-timer.c:662
#9  0x000055ed03faf8da in main_loop_wait (nonblocking=<optimized out>) at /usr/src/debug/qemu-2.9.1/util/main-loop.c:525
#10 0x000055ed03c2f0e3 in main_loop () at /usr/src/debug/qemu-2.9.1/vl.c:1898

-Andi